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What Is This Weird File Name in My Samba Share?

In IT there are big things and there are small things. Some small things can be pretty annoying and they seem to stay here forever.  One of these annoying little things is difference between restrictions for file names in Windows versus  unix/linux (others are for instance legacy character encodings, http proxy support, these things has teased me many times in past).  Have you ever seen strange file name like W3NEM5~I on shared disc instead of meaningful file name, that you expected? If so and you’re interested what’s going on continue reading. Continue reading What Is This Weird File Name in My Samba Share?

Linux Desktop for 2017 and on

Screenshot from 2017-10-08 08-38-43As Canonical has announced the end of Unity desktop I thought it’s time to look again around at Linux desktops. In past years I have been using mainly Gnome 2 (or Mate recently), XFCE, Cinnamon and Unity (yes I did and experience was after all rather positive). I’ve tried Gnome 3 few years ago, but really never gave it longer try and never really find attraction for KDE. So in this article I’ll look a bit at those desktops again and especially at the recent Gnome Shell and it’s customization to my needs (which is indeed based on very individual preferences). Continue reading Linux Desktop for 2017 and on

Beware of sync option in mount

By default mount is using async option, which means that  write operations do not wait for final confirmation from the device – they are stored in disc cache and writes are done latter, optimized by disc firmware.  However you can set sync option manually ( -o sync), then write operations are synchronous, meaning each block write has to wait for confirmation that it’s physically written to the  disc and there is no optimization available.  This can significantly slow down write speed, of which I convinced myself just recently – I backuped  some data to external 2.5″ USB 3.0 HD – slowdown in this case was almost 1000x  –  (70kb/s vs 60MB/s   measured by rsync --progress).  How it happened that disc was mounted with sync option? I actually use usbmount to auto-mount disks and it has sync as default mount option (fortunately can be changed in it’s configuration). So conclusion is – don’t use sync  option unless you know exactly what you are doing and if write speed is suspiciously slow check mount options.

Secret Sharing Is Caring Too

In todays digital world passwords and other types of secrets are omnipresent and they secure access to various assets dear to our hearts, some of those can have tremendous tangible or moral value. For such assets it’s worth to select really good and strong password, which basically means long and hard to remember. How to ensure ourselves in case of memory failure? We can write it down and lock in secure place, share with trusted person etc., but still there is one point of of failure – secure place can be robbed, that person can betray us. Can cryptography  provide us with better options?  Yes it can with help of method called Secret sharing – we can split secret into n parts – called shared secrets – and distribute them to different places/people. Later we (or someone else) need to collect k (k > 0 and k <= n) shared secret to recover original secret. k is called threshold and it is defined when generating shared secrets – so we for instance generate n=5 shared secrets, but only k=3 will be needed to recover original secret.

I believe you can easily imagine  many other real life scenarios where secret sharing can be useful and for sure it’s used in many applications and systems today. Cryptography provides several algorithms for secure (by design) secret sharing.  Most common is Shamir’s Secret Sharing based on linear algebra approach. There are many tools and libraries for Shamir’s scheme (and further advancements of original algorithm),  you can for instance try ssss, which provides command line tool that you can easily install into your Linux and also there is an online demo. Another family of secret sharing schemes is based on Chinese Reminer Theorem, where especially Asmuth-Bloom scheme is interesting.  I have not seen many implementation for Asmuth-Bloom secret sharing so I created one in Rust. Continue reading Secret Sharing Is Caring Too

The Splendors and Miseries of CaaS – Experiences with Openshift3

Container as a Service (CaaS) is increasingly popular cloud service (usually categorized under Platform as a Service family of cloud services). It can provide easy ways how to deploy web applications leveraging Linux container technologies usually most popular Docker containers.  Recent addition to this family is Openshift v3 from RedHat.   Openshift is available as an open source  software (Openshift Origin) or as a hosted service (OpenShift Online).  I already used previous version of Openshift service (v2), as described in my previous article. In this article I’ll share my recent experiences with Openshift v3 service (also called NextGen). Continue reading The Splendors and Miseries of CaaS – Experiences with Openshift3

Ethereum local playground

In past article I’ve talked generally about blockchain technologies, in this article we will look into Ethereum from user perspective. We will build local playground, where we can test many functions of Ethereum(Ethers transfers, using and writing smart contracts and more) without spending real Ethers (and thus real money). This guide in intended for users with Linux OS. Continue reading Ethereum local playground

Blockchain madness

Some technologies I really notice only when they hit me directly into the face.   That’s the case of blockchain  –  I have been looking into Bitcoin several years back and found it quite interesting (especially from cryptographic perspective – as interesting usecase for applied cryptography), but never expected that it’ll reach such extensive grow in popularity as we have seen in past half year or so.   This forced me to looked again into these technologies and get bit more detailed understanding about blockchain technologies, why it’s so popular now and particularly look at recent development and on  next big player in this area Ethereum project.

In this article I’ll share some initial thoughts of mine about blockchain, what I think it is and why it matters. In later article(s) we’ll look into  Ethereum from purely practical perspective. We will build a local playground for Ethereum, where we can try immediately some basic functions of the system. Continue reading Blockchain madness

In RUST We Trust

Having been programing recently mostly in dynamic untyped languages (aka Python and JavaScript) I though that it would be nice to try something else, bit different –  meaning compiled and statically typed. Last adventures in this area were with OCAML, which I used for few learning projects couple years ago( like this one).  OCAML is very nice language indeed, and learning exercise was very valuable for me (especially getting more accustomed to functional programming style),  but apart  of that learning experience I did not follow it  further (mainly due limited ecosystem of OCAML).

Looking recently to languages and technology survey on Stackoverflow  where Rust is leading the list of most “loved” languages (meaning developers who used the language like it and want to use it for their next projects) with head start on   second one (SmallTalk) .   This caught my attention and looking quickly at Rust site I decided to give it a try.  Below are my first experiences learning this language. Continue reading In RUST We Trust

Run and monitor tasks via WebSocket with ASEXOR

Many modern web applications require more then just displaying data in the browser.  Data may need to be processed and transformed in various ways, which require intensive processing tasks on server side. Such processing is best done asynchronously outside of web application server, as such tasks can be relatively  long running. There are already many existing solutions for asynchronous task scheduling, some of them are quite sophisticated general frameworks like Celery, Kafka, others are build in features of application servers ( like mules and spoolers in uWSGI).  But what if we need something simpler, which can work  directly with Javascript clients and is super simple to use in a project.  Meet asexor – ASynchronous EXecuOR,  a small project of mime. Continue reading Run and monitor tasks via WebSocket with ASEXOR